Description of the first global outbreak of mpox: an analysis of global surveillance data
Authors: Henry Laurenson-Schafer, Nikola Sklenovská, Ana Hoxha, Steven M Kerr, Patricia Ndumbi, Julia Fitzner, Maria Almiron, Luis Alves de Sousa, Sylvie Briand, Orlando Cenciarelli, Soledad Colombe, Meg Doherty, Ibrahima Soce Fall, Christian García-Calavaro, Joana M Haussig, Masaya Kato, Abdi Rahman Mahamud, Oliver W Morgan, Pierre Nabeth, Jeremias Domingos Naiene, Wildo Araujo Navegantes, Opeayo Ogundiran, Charles Okot, Richard Pebody, Tamano Matsui, Hugo López-Gatell Ramírez, Catherine Smallwood, Raúl Francisco Pérez Tasigchana, Aisling M Vaughan, George Sie Williams, Peter Omondi Mala, Rosamund F Lewis, Boris I Pavlin, Olivier le Polain de Waroux, Basma Abdelgawad, Amarnath Babu, Evans Buliva, Finlay Campbell, Daniel Cardoso Portela Câmara, Zainab Eleiba, Blanche Johanna Greene-Cramer, Esther Hamblion, Mahmoud Hassan, Kaja Kaasik-Aaslav, Basant Mohamed, Victoria Ndarukwa, James Richard Otieno, Jeffrey Pires, Jukka Pukkila, Felix Sanni, Craig Schultz, Tika Sedai, Laila Skrowny, Manilay Phengxay, Ariuntuya Ochirpurev, Jozica Skufca, Laura Goddard, Viema Biaukula
Journal: The Lancet Global Health (2023)

BackgroundIn May 2022, several countries with no history of sustained community transmission of mpox (formerly known as monkeypox) notified WHO of new mpox cases. These cases were soon followed by a large-scale outbreak, which unfolded across the world, driven by local, in-country transmission within previously unaffected countries. On July 23, 2022, WHO declared the outbreak a Public Health Emergency of International Concern. Here, we aim to describe the main epidemiological features of this outbreak, the largest reported to date.MethodsIn this analysis of global surveillance data we analysed data for all confirmed mpox cases reported by WHO Member States through the global surveillance system from Jan 1, 2022, to Jan 29, 2023. Data included daily aggregated numbers of mpox cases by country and a case reporting form (CRF) containing information on demographics, clinical presentation, epidemiological exposure factors, and laboratory testing. We used the data to (1) describe the key epidemiological and clinical features of cases; (2) analyse risk factors for hospitalisation (by multivariable mixed-effects binary logistic regression); and (3) retrospectively analyse transmission trends. Sequencing data from GISAID and GenBank were used to analyse monkeypox virus (MPXV) genetic diversity.FindingsData from 82 807 cases with submitted CRFs were included in the analysis. Cases were primarily due to clade IIb MPXV (mainly lineage B.1, followed by lineage A.2). The outbreak was driven by transmission among males (73 560 [96·4%] of 76 293 cases) who self-identify as men who have sex with men (25 938 [86·9%] of 29 854 cases). The most common reported route of transmission was sexual contact (14 941 [68·7%] of 21 749). 3927 (7·3%) of 54 117 cases were hospitalised, with increased odds for those aged younger than 5 years (adjusted odds ratio 2·12 [95% CI 1·32–3·40], p=0·0020), aged 65 years and older (1·54 [1·05–2·25], p=0·026), female cases (1·61 [1·35–1·91], p<0·0001), and for cases who are immunosuppressed either due to being HIV positive and immunosuppressed (2·00 [1·68–2·37], p<0·0001), or other immunocompromising conditions (3·47 [1·84–6·54], p=0·0001).InterpretationContinued global surveillance allowed WHO to monitor the epidemic, identify risk factors, and inform the public health response. The outbreak can be attributed to clade IIb MPXV spread by newly described modes of transmission.FundingWHO Contingency Fund for Emergencies.TranslationsFor the French and Spanish translations of the abstract see Supplementary Materials section.